Straight pipe on diesel - Page 2 - TigerDroppings.com

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YOURADHERE
LSU Fan
Member since Dec 2006
2784 posts

re: Straight pipe on diesel


Any noticable difference in mileage? I have a '12 F250 and have been thinking about a CAI. If for anything just so I have have a wash/reuse air filter versus buying a new $50 throw-away one every 10,000 miles or so.





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Chad504boy
New Orleans Saints Fan
Five Oh Four
Member since Feb 2005
79285 posts

re: Straight pipe on diesel


quote:

Any noticable difference in mileage?


little bit, ever so little bit. It should pay itself off in 8 years.






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Hammertime
LSU Fan
apples
Member since Jan 2012
14997 posts

re: Straight pipe on diesel


IMHO, cold air intakes are worthless unless you have a way for that air to get out of the back, which in gradually has less and less of with the DPF.

The air comes from your engine compartment on most of them, so TIFWIW






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YOURADHERE
LSU Fan
Member since Dec 2006
2784 posts

re: Straight pipe on diesel


Sounds like a wise investment, I'll take two.

In regards to the better fuel milege on the 6.7, if you're not looking to go the tuner/DPF delete route then my only suggestion would be to slow down. I noticed a decent gain in my 6.7 by doing so. For example when I'd run 75-78mph down the interstate I'd get about 15mpg, by keeping it under 70(~68mph) it jumped to about 18-19mpg on the interstate. Then I lifted it and now it's about 14mpg regardless of how I drive it.






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tiger94gop
LSU Fan
GEISMAR
Member since Nov 2004
1676 posts

re: Straight pipe on diesel


Unless you change the gearing, nothing anyone does will gain significant mileage. I don't bleieve Chips, exhaust, etc. make a "significant" difference. Once you do the mods, you become more aware of your mileage. Depending on the model, you are asking for an 8,000 lb vehicle to get better fuel mileage. The earlier Power Strokes got good mileage because they had 355 gears. Everything since they changed to the superduty body style has either 373/410 gears. That is why a dually gets 8 pulling or empty. If it is a 4wd, you would have to change both sets of gears. They actually make a transmission add-on that adds extra gears, a set of high gears like a big truck. It costs about $3500 and adds about 4-5 mpg. If you are hot-shotting or pulling it is worth it. If 2wd, and you never pull, just change the rear end.

Ford doesn't offer the 6 speed tramsmissions, Chevy's Allison is great, but I am not sure about the number of gears I think it is four, Dodge is now offering a 6 speed.

You can spend $5k on a Ford to get a few mpg and increase HP. You can spend $150 on Dodge or Chevy and get twice the performance increase of the Ford. They are different engines. Your can get amazing number out of the Cummins for very little money. The Chevy is fast normally and a chip will let you beat mustangs on the jump, gas trucks don't stand a chance. Ford is a v-8 it just isn't as efficient as the straight 6 Dodge or Chevy.

I've have seen a video of a Ford Dually that gets 29 mpg, they spent $12k in engine mods, body panels, and 340 something gearing (can't remember exact #'s). The gearing made the difference and not needing low gears or not pulling with it ever, justifies the expense if it is an everyday driver. Also, you could technically haul light loads, you won't hurt a Diesel with low end strain trying to take off, it just takes a long time to get rolling.






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DownshiftAndFloorIt
LSU Fan
The devil dreams on an idle horse
Member since Jan 2011
39276 posts

re: Straight pipe on diesel


You've got some bad info there.

quote:

Ford doesn't offer the 6 speed tramsmissions


They are all double OD 6 speeds.

The allison is a single OD 6 speed and so is the dodge.

There's some other misinformation there, but that's a big one. The ford is a double overdrive.






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tiger94gop
LSU Fan
GEISMAR
Member since Nov 2004
1676 posts

re: Straight pipe on diesel


That is new, or in the latest version off the Super Duty so his truck may have it at 2012. I knew a Dodge had it, wasn't sure about the Allison.

So it doesn't matter, the rear end still kills it.






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Chad504boy
New Orleans Saints Fan
Five Oh Four
Member since Feb 2005
79285 posts

re: Straight pipe on diesel


quote:

So it doesn't matter, the rear end still kills it.


you talking about my trucks rear end bro?






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DownshiftAndFloorIt
LSU Fan
The devil dreams on an idle horse
Member since Jan 2011
39276 posts

re: Straight pipe on diesel


quote:

the rear end still kills it.


It certainly doesn't help. The purpose of a diesel IMO is that you don't need that low rear end to pull. 4.10's belong on gas burners. Diesels have gobs of low end torque and really don't care how much you "bog" them. Diesels don't need to rev like a gas burner. The duramax has a pretty high power curve for a diesel though which is why you get that neck snapping top end out of them.

People want their trucks to take off like corvettes these days though, so you'll find plenty of 3/4 ton diesels out there with 3.73's and even 4.10's in them when they should be wearing 3.42's.

Even still, you're not going to get the mileage you got in the old diesels, even with highway gears. They're EPA'd to death.






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tiger94gop
LSU Fan
GEISMAR
Member since Nov 2004
1676 posts

re: Straight pipe on diesel


I would love to find a 2002, 2wd f-250 that hasn't been hurt. Put light gears in it and get low to mid 20's on the highway after changing dowpipe, adding 4inch exhaust and a few other mods. You could drive that truck forever and justify the additional expense of the Diesel.

I had a 4wd did everything but the gears and kept it under 70 and best I ever got was 19.






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